Trocar cannula assembly with low profile insertion configuration and method of manufacture

ABSTRACT

A cannula assembly having a retention member and a method of manufacture of the cannula assembly is provided. The cannula assembly includes a cannula and a sleeve disposed around the cannula from a proximal end to a distal end. The sleeve can include a balloon formed by a stretch blow molding process following local heating once advanced over the cannula. Once formed, the balloon can be conditioned to constrict against the cannula. A conditioning aid can be advanced over the balloon when it is still formable to constrict the balloon against the cannula.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/792,285, entitled “TROCAR CANNULA ASSEMBLY WITHLOW PROFILE INSERTION CONFIGURATION AND METHOD OF MANUFACTURE,” filed onMar. 15, 2013. The entirety of this prior application is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

This application relates generally to surgical access systems andmethods of manufacturing such systems and, more specifically, to balloontrocars with retention components and methods of manufacturing the same.

Description of the Related Art

Surgical access systems such as trocar systems facilitate minimallyinvasive surgery across a body wall and within a body cavity. Forexample, in abdominal surgery, trocars provide a working channel acrossthe abdominal wall to facilitate the use of instruments within theabdominal cavity. Trocar systems typically include a cannula, whichprovides the working channel, and an obturator that is used to place thecannula across a body wall, such as the abdominal wall. The obturator isinserted into the working channel of the cannula and pushed through thebody wall with a penetration force of sufficient magnitude to result inpenetration of the body wall. Alternatively, the cannula with anobturator is passed through an incision formed by the “Hasson,” orcut-down, technique, which includes incremental incisions through thebody wall until the body wall is incised through its entire thickness.Once the cannula has traversed the body wall, the obturator can beremoved.

With the cannula in place in the body wall, various instruments may beinserted through the cannula into the body cavity. One or more cannulaemay be used during a procedure. During the procedure, the surgeonmanipulates the instruments in the cannulae, sometimes using more thanone instrument at a time. The manipulation of an instrument by a surgeonmay cause frictional forces between the instrument and the cannula inwhich the instrument is inserted. These frictional forces may result inmovement of the cannula in an inward or outward direction within thebody wall. If the cannula is not fixed in place, the proximal or distalmotions of the instruments through the cannula may potentially cause thecannula to slip out of the body wall or to protrude further into thebody cavity, possibly leading to injury to the patient.

The surfaces of the cannula associated with a trocar are generallysmooth. The smoothness of a cannula surface makes placement of thecannula through a body wall relatively easy and safe. However, a smoothcannula may not have the desired retention characteristics once thecannula has been placed through a body wall. This smoothness and ease ofplacement may present problems as instruments and specimens are removedfrom a body cavity through the cannula and the associated seal systemsof the trocar. It is highly desirable for a cannula to remain fixed inan appropriate position once placed. Additionally, if the Hassontechnique is used, the incision may be larger than the cannula that maybe placed through the incision. Therefore, it is desirable to provide ameans to seal the incision site after the cannula has been inserted inorder to insufflate a patient.

Various solutions to the issue of trocar-cannula fixation orstabilization have been attempted. These attempts include an inflatableballoon attached to the distal portion of the cannula with a thick foambolster proximal to the insertion point into the body wall, raisedthreads or raised rings associated with the outer surface of thecannula, mechanically deployable enlarging portions arranged at thedistal end of a cannula and suture loops or hooks associated with theproximal end of the trocar. These attempts have provided some degree offixation or stabilization, but they have often led to cannulae having arelatively large outside diameter. Further, the thick foam bolsterassociated with balloon trocars has reduced the usable length of thecannula. There remains a need for a cannula fixation or stabilizationdevice that includes a sleeve having retention means that minimize theincrease in diameter. Additionally, the cannula fixation orstabilization device may include a lower profile and increase theworking length of the cannula.

Methods for achieving the above comprise inflatable toroidal balloonsthat are sized larger than the cannula associated with the access deviceand usually disposed at or toward the distal end thereof. Duringinsertion of the access channel through a body wall, the balloon isdeflated. The balloon is inflated when the access channel is within thebody cavity and properly placed. Most of the balloons associated withaccess devices are distensible or made of an elastic material. In somecases the balloons are made of a non-distensible or non-elasticmaterial.

SUMMARY OF THE INVENTION

A balloon trocar, in various embodiments in accordance with the presentinvention, can be used in general, abdominal, gynecological and thoracicminimally invasive surgical procedures to establish a path of entry orto gain access through the tissue planes and/or potential spaces forendoscopic instruments. In various embodiments, a balloon trocarcomprises an inflatable balloon at the distal end of a trocar cannulaand a bolster toward the proximal end of the cannula. To use the balloontrocar, a surgeon inserts the balloon trocar into the body cavity suchthat the balloon section of the cannula is within the cavity, e.g., forabdominal surgery, beyond the peritoneal lining and within the abdominalcavity. The balloon is inflated and the bolster located toward theproximal end of the cannula is moved distally along the length of thecannula in order to compress the balloon against the inside of the bodywall and seal the incision. With the bolster against the outer surfaceof the body wall, the balloon is maintained in compression against theinner surface of the body wall. In this manner, a seal is createdbetween the balloon and the body wall, thereby allowing a surgeon toinsufflate a patient. The balloon may remain inflated during theduration of a laparoscopic surgery, which may last up to four hours ormore.

An elastic balloon is formed as a small inflatable structure. Whendeflated, an elastic balloon assumes a natural “low-profile” conditionand conforms to the outer surface of the access channel or cannula. Anon-elastic balloon is formed to assume a preferred maximum size andshape in a natural condition. Therefore, there exists a surplus ofnon-elastic balloon material when the balloon is deflated. As such,non-elastic balloon structures associated with an access channel thatclosely conforms to the exterior of the access channel and minimizes theinterference between the deflated balloon and the tissue of a body wallduring the insertion of the access device are desirable.

In accordance with various embodiments of the present invention, aballoon trocar is provided in which the balloon or retention componentreduces insertion force of the balloon trocar. In one embodiment, aballoon or expandable membrane positioned on or near the distal end ofthe cannula of the trocar is void or without or having little air withinthe balloon and is folded proximally or away from the direction in whichthe trocar is to be inserted into the body cavity. The evacuation of airand folding of the balloon reduces resistance and the insertion forceused to insert the cannula within the body cavity without reducingballoon strength to maintain retention by the balloon and integrity ofthe seal and the balloon itself. Additionally, such a balloon permitsthe utilization of a reduced insertion force relative to the insertionforce of a non-folded balloon. A reduced insertion force permits a morecontrolled entry of the trocar into the body cavity. A more controlledentry reduces inadvertent and undesirable contact with organs, tissue,other inserted devices or ports within the body cavity. Also, a reducedinsertion force reduces potential trauma to the incision or entry siteas less force is applied to the site as the trocar is being insertedinto the body cavity.

In various embodiments, an access channel or cannula that is associatedwith a surgical access device or trocar is provided. The cannula issized and configured to receive a retention and stabilizing balloonalong the distal portion. A non-elastic balloon made of polyolefin,nylon, polyester, polyethylene or the like is placed along a locationupon the cannula. The deflated non-elastic balloon is maintained in thelowest profile condition for insertion through a body wall. The balloonconforms very closely the profile of the cannula. A folded ballooncondition is maintained.

In certain embodiments, a cannula assembly is provided. The cannulaassembly comprises a cannula and a sleeve. The cannula has a proximalend, a distal end opposite the proximal end, and a lumen extending fromthe proximal end to the distal end along a longitudinal axis. The lumenis configured to receive a surgical instrument therein. The cannulacomprises a generally tubular cannula body and an annular recess. Thegenerally tubular cannula body has an exterior surface and a first outerdiameter. The annular recess is formed in the exterior surface of thecannula body adjacent the distal end of the cannula. The annular recessis transverse to the longitudinal axis. The annular recess has a secondouter diameter smaller than the first outer diameter of the cannulabody. The sleeve has a proximal end and a distal end. The sleeve isdisposed around the cannula from adjacent the proximal end of thecannula to the annular recess. The sleeve comprises an elongate tubularbody and a balloon positioned distal the elongate tubular body. In someembodiments, the sleeve further comprises a chamfered leading edge atthe distal end of the sleeve. In some embodiments, the annular recesshas a textured surface adapted to receive an adhesive. In someembodiments, the cannula assembly further comprises a conditioning aidremovably disposed around the balloon. The conditioning aid is sized tocompress the balloon proximally along the exterior surface of thegenerally tubular cannula body in a snug fit defining a low diameterinsertion profile.

In certain embodiments, a method of making a cannula assembly having aninflatable balloon is provided. The method comprises positioning agenerally tubular sleeve over a cannula, bonding the sleeve to thecannula, locally heating a predetermined length of the tubular sleeve,applying a source of inflation fluid to the tubular sleeve to form aballoon, and conditioning the balloon to constrict against the cannula.The generally tubular sleeve has a proximal end and a distal end. Thecannula has a proximal end and a distal end and comprises an elongatecannula body with an annular groove formed in the cannula body at thedistal end of the cannula. Bonding the sleeve to the cannula comprisesbonding the proximal end and the distal end of the sleeve to thecannula. Locally heating the tubular sleeve comprises locally heating apredetermined length of the tubular sleeve adjacent the distal end ofthe tubular sleeve. The balloon is formed adjacent the distal end of thetubular sleeve. After forming the balloon and while the balloon retainsresidual heat from the local heating, the balloon is conditioned toconstrict against the cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a laparoscopic surgical procedure;

FIG. 2 illustrates a plan view of a laparoscopic surgical procedureshowing the placement of trocars;

FIG. 3 illustrates a perspective view of a prior art assembled trocarand obturator;

FIG. 4 illustrates a perspective view of a prior art assembled trocarwithout an obturator;

FIG. 5 illustrates a perspective view of a prior art cannula;

FIG. 6 illustrates a perspective view of a prior art assembled threadedtrocar and obturator;

FIG. 7 illustrates a perspective view of a prior art threaded cannulaand housing;

FIG. 8 illustrates a perspective view of a prior art threaded cannula;

FIG. 9 illustrates a perspective view of a prior art cannula having anuninflated balloon at the distal end;

FIG. 10 illustrates a perspective view of a prior art cannula having aninflated balloon at the distal end;

FIG. 11 illustrates a prior art trocar-cannula having a distal retentionballoon placed through a body wall in a first position;

FIG. 12 illustrates a prior art trocar-cannula having a distal retentionballoon placed through a body wall in a second position;

FIG. 13 illustrates a perspective view of an embodiment of trocarcannula assembly;

FIG. 14 illustrates a perspective view of an embodiment of sleevesubassembly of the trocar cannula assembly of FIG. 13;

FIG. 15 illustrates a perspective view of an embodiment of cannula ofthe trocar cannula assembly of FIG. 13;

FIG. 16 illustrates a detail cut away view of a distal end of thecannula of FIG. 15;

FIG. 17 illustrates a detail cut away view of the trocar cannulaassembly of FIG. 13;

FIG. 18 illustrates a partial cross-sectional view of an embodiment oftrocar cannula assembly in a partially-assembled configuration;

FIG. 19 illustrates a partial cross-sectional view of the distal end ofthe trocar cannula assembly of FIG. 13;

FIG. 20 illustrates a perspective view of a conditioning aid of thetrocar cannula assembly of FIG. 13;

FIG. 21 illustrates a perspective view of a retention disk of the trocarcannula assembly of FIG. 13;

FIG. 22 illustrates a cross-sectional view of the retention disk of FIG.21;

FIG. 23 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration;

FIG. 24 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state;

FIG. 25 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state;

FIG. 26 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a deflated state and a conditioning aid advanced over theballoon;

FIG. 27 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configurationundergoing a sterilization process;

FIG. 28 schematically illustrates a distal end of an embodiment oftrocar cannula assembly in a partially-assembled configuration with aballoon in a folded insertion configuration;

FIG. 29 illustrates an embodiment of a method for manufacturing a trocarcannula assembly;

FIG. 30 illustrates an embodiment of a method for manufacturing a trocarcannula assembly; and

FIG. 31 illustrates an exemplary graph of an insertion force in poundsversus insertion depth for various trocar cannulae.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, a typical laparoscopic procedure isillustrated where a plurality of trocars 100 are placed through a bodywall 50, such as an abdominal wall, and into a body cavity 52, such asan abdominal cavity. The body cavity 52 is insufflated, or inflated withgas, to distend the body wall 50 and provide a working space for thelaparoscopic procedure. The trocars 100 each include a cannula 110 and aseal 150. Positive pressure is maintained within the body cavity 52 bythe seal 150 associated with the cannula 110. In addition, the cannula110 must form a gas-tight seal against adjacent tissue. If positivepressure is lost, either through the seal 150 associated with thecannula 110 or the seal between the cannula and the adjacent tissue, theprocedure may be compromised.

As the body cavity 52 is inflated, the body wall 50 may be greatlydistended. The access sites may tend to enlarge under the distention ofthe body wall 50 and compromise the positioning and sealing of thecannula 110. As stated above, the manipulation of instruments 190 usedthrough the trocars 100 may result in movement of the cannulae 110 ineither a proximal or distal direction within the access site through thebody wall 50. As this occurs, some liquefaction may take place and thepreferred relationship between the cannula 110 and the body tissue maybe compromised.

Referring now to FIGS. 3-6, a typical assembled trocar 100 is shownhaving a cannula 110, a seal housing 150 and an obturator 160. Thecannula 110 typically has a smooth exterior surface 102 so that it maybe inserted through the body wall 50 easily. The seal housing 150contains a seal system that prevents retrograde gas-flow. The obturator160 is a cutting or piercing instrument that creates the pathway throughthe body wall 50 through which the cannula 110 follows. Surgicalobturators 160 are generally sized and configured to create a defect intissue that is appropriate for the associated cannula 110. However, thedefect may have a tendency to enlarge during a surgical procedure as thetrocar 100 or cannula 110 is manipulated. As an instrument 190 is urgeddistally and proximally, or inserted and withdrawn, the cannula 110 maymove or even be inadvertently withdrawn due to the friction between theinstrument 190 and the seal 150 of the trocar housing.

With specific reference to FIGS. 6-8, a trocar 100 or access device isshown where the outer surface 102 of the cannula 110 includes aplurality of raised features 115. These raised features 115 are sizedand configured to increase resistance to proximal and distal motion asinstruments 190 are maneuvered, and especially as specimens are removed,through the trocar 100. The prior art includes either sequential raisedrings or a raised coarse-thread 115. While the rings or threads 115 ofthe prior art may stabilize the cannula 110 to some degree, they do notnecessarily seal the cannula 110 against the adjacent tissue of a bodywall 50. There may be gas loss associated with the use of these systems.The raised rings or threads 115 also increase the insertion forcerequired to penetrate a body wall 50. The insertion force may be reducedin the instance of a continuous coarse thread 115 in comparison to asequence of discrete raised rings or features as a threaded cannula 110may actually be “screwed” into the tissue defect in accordance with thethread direction and pitch, rather than pushed through withoutappropriate rotation.

With reference to FIGS. 9-12, a surgical access device 100 according toprior art includes a cannula 110 having an inflatable balloon 120associated with the distal-end portion 122 of the cannula. The balloon120 is sized and configured to fit snugly around the cannula 110 in theuninflated condition. The balloon 120 is inflated after the cannula 110is properly placed through the body wall 50 and into the body cavity 52.The balloon 120 is generally held against the interior surface 54 of thebody wall 50 by a counter-force that is associated with a slidingcounter-force member, such as a foam bolster 180. The bolster 180 isassociated with the proximal portion of the cannula 110. The balloons120 associated with the devices of the prior art are typically“thick-walled” structures constructed as part of the cannula 110. Theballoon 120 is generally bonded to the distal-end portion 122 of thecannula 110 and an inflation channel or lumen is provided within thewall of the cannula 110.

With reference to FIG. 13, an embodiment of trocar cannula assembly 210having advanced fixation features is illustrated. The trocar cannulaassembly 210 can include a seal housing 212 and a sleeve sub assembly214 comprising a trocar cannula 216, a sleeve 218 including aninflatable balloon 220, a retention disc 222, and a tip protector 224 orconditioning aid. Various aspects described herein with respect tocertain embodiments of trocar cannula assembly can be used in eitherballoon cannulae or retention cannulae.

With continued reference to FIG. 13, the seal housing 212 or valvehousing can include an instrument seal and a zero seal. In someembodiments, the valve housing can be removably coupled to the cannula216 and in one embodiment includes an inlet for supplying insufflationgas into a body cavity such as the abdominal cavity. The instrument sealand zero seal enclosed in the valve housing in various embodiments canbe separate or monolithic seals. The zero seal and instrument seal canseal an instrument path through the valve housing into a lumen 236 (FIG.14) of the cannula 216. In other embodiments, the trocar cannula 216 canhave an instrument seal and a zero seal, separate or monolithic seals,positioned directly therein with no separate valve housing such that thetrocar cannula with a sealed instrument channel path has a relativelyshort length from a proximal end to the distal end defining a low heightprofile.

In certain embodiments, the trocar cannula assembly 210 can be sized toreceive surgical instruments such as laparoscopic surgical tools havingstandard sizes. For example, the trocar assembly 210 can be a “5 mmtrocar cannula,” sized and configured to receive surgical tools fromsized up to a 5 mm surgical tool product class. In other embodiments, atrocar assembly 210 can be an “11 mm trocar cannula” or a “12 mm trocarcannula,” sized and configured to receive surgical tools sized as largeas an 11 mm or 12 mm surgical tool product class respectively. In someembodiments, the trocar cannula assembly 210 can be included in a kitcomprising the trocar cannula assembly 210, a seal housing 212 and anobturator insertable through the seal housing 212 and the cannulaassembly 210.

With reference to FIGS. 13-14, the trocar cannula 216 can include afluid inlet port 226. The fluid inlet port 226 is adapted to receive asource of fluid such as a syringe. The fluid can comprise air, anothergas such as carbon dioxide, a gas mixture, or a liquid such as water, asaline solution, or another liquid solution. As further discussedherein, the fluid inlet port 226 is fluidly coupled to the sleeve 218such that addition of fluid to the fluid inlet port 226 inflates theballoon 220.

In some embodiments, the fluid inlet port 226 can include a one-wayvalve such as a poppet valve or check valve 228. Once fluid is added tothe fluid inlet port 226 through the check valve 228, the check valve228 maintains the fluid within the sleeve 218 and balloon 220 of thetrocar cannula assembly 210. The check valve 228 can be selectivelyopened to allow the fluid to escape or be withdrawn such as by syringewhen it is desired to deflate the balloon 220.

Trocar Cannula

With reference to FIG. 15, in some embodiments, the trocar cannula 216has a proximal end 230, a distal end 232, and a lumen 236 extending fromthe proximal end 230 to the distal end 232 along a longitudinal axis L.The lumen 236 is configured to receive a surgical instrument thereinsuch as a laparoscopic surgical tool.

With continued reference to FIG. 15, in some embodiments, the trocarcannula 216 comprises a seal housing interface 238 at the proximal end230, the fluid inlet port 226 distal the seal housing interface 238, agenerally tubular cannula body 240 extending distally from the fluidinlet port 226, an annular recess such as an annular groove 242 in thecannula body 240 adjacent the distal end 232 of the cannula 216, and adistal tip 244. The seal housing interface 238 can comprise a seal suchas an O-ring 246 (FIG. 14) to sealingly engage a seal housing.

In the illustrated embodiments, the fluid inlet port 226 comprises afluid inlet 250 and a fluid dome 252. The fluid inlet 250 is configuredto receive the source of inflation fluid and can include the check valve228 positioned therein (FIG. 14).

As illustrated, the fluid dome 252 of the fluid inlet port 226 isfluidly coupled to the fluid inlet 250. In some embodiments, the fluidinlet port 226 can have a generally smooth outer surface 254. The smoothouter surface 254 can allow adhesive to flow underneath the sleeve 218and obtain a relatively strong balloon-to-cannula bond. In someembodiments, the fluid inlet port 226 can be shaped with a curvedprofile such as a generally teardrop shape and the fluid dome 252 canhave a curved profile to reduce the likelihood of the fluid pathway forballoon inflation/deflation can become plugged. In other embodiments,the fluid inlet port 226 can have another curved profile such as agenerally cylindrical, elliptical, or oval profile. In otherembodiments, the fluid inlet port 226 can have another curvilinearprofile.

Cannula Body

With continued reference to FIG. 15, in some embodiments, the cannulabody 240 extends distally from the fluid inlet port 226 to the distalend 232 of the cannula 216. The cannula body 240 has an exterior surface260 and a first outer diameter D1. In some embodiments, the exteriorsurface 260 of the cannula body 40 can be configured to facilitateinstallation of the sleeve 218 thereon. For example, the exteriorsurface 260 of the cannula body 240 can include a relatively lightlytextured surface finish to facilitate sliding advancement of the sleeve218 over the cannula body 240.

In some embodiments, the cannula body 240 can include one or more fluidchannels 262 or grooves that extend generally longitudinally from thefluid inlet port 226 towards the distal end 232 of the cannula 216. Thefluid channel 262 can be formed in the exterior surface 260 of thecannula body 240 and extend a depth d into the cannula body 240. Asillustrated, the fluid channel 262 is fluidly coupled to the fluid inletport 226 and extends distally to a location adjacent the balloon 220 ofthe sleeve 218. (FIG. 14). The fluid channel 262 can thus work inconjunction with the balloon 220 to allow fluid passage for balloon 220inflation and deflation. Advantageously, with the fluid channel 262embedded in the cannula body 240, the sleeve sub-assembly 214 can have arelatively small outer diameter and low-profile. Desirably, with arelatively small diameter and low-profile, the cannula assembly 210 canhave a relatively low insertion force. Similarly, the balloon 220 andfluid channel 262 geometry can reduce the incidence of the balloon 220plugging the fluid flow path during deflation.

With continued reference to FIG. 15, the cannula body 240 can include anannular recess such as an annular groove 242 adjacent the distal end ofthe trocar cannula 216. In some embodiments, the annular groove 242 isformed in the cannula body 240 at an orientation generally perpendicularto the longitudinal axis L of the trocar cannula 216. In otherembodiments, other orientations of the annular groove 242 can be formed.In certain embodiments, as illustrated, the annular recess comprises anannular groove 242 having a recessed surface extending a relativelyshort length along the longitudinal axis L of the trocar cannula 216adjacent the distal end of the trocar cannula 216. In other embodiments,the annular recess or annular groove can include a recessed surfaceextending from a location adjacent the distal end proximally to alocation between the proximal end or the distal end of the trocarcannula 216 or to a location adjacent the proximal end of the trocarcannula 216.

FIG. 16 illustrates a cut away detail view of an embodiment of annulargroove 242. In some embodiments, the annular groove 242 can have aproximal edge 270, a distal edge 272, and an annular interface surface274 between the proximal edge 270 and the distal edge 272. The annularinterface surface 274 can have a second outer diameter D2 smaller thanthe first outer diameter D1 of the cannula body 240. The proximal edge270 can have a generally stepped edge extending between the first outerdiameter D1 of the cannula body 240 and the second outer diameter D2 ofthe annular interface surface 274. Desirably, the stepped edge canenhance sealing performance of the sleeve 218 to the cannula body 240 tomaintain fluid within the balloon 220 in an inflated configuration.

With continued reference to FIG. 16, in some embodiments, the distaledge 272 of the annular groove 242 can have a ramped edge. The rampededge can extend at an angle transverse to the annular interface surface274. In other embodiments, the distal edge 272 of the annular groove 242can comprise a generally stepped edge or an edge having anothergeometric profile such as a radiused curvilinear edge.

With reference to FIG. 15, in some embodiments, the distal tip 244 atthe distal end 232 of the cannula 216 has a distal edge 278 that extendsat an angle θ relative to a plane perpendicular to the longitudinal axisL of the cannula 216. The angle θ can be between about 5 degrees andabout 45 degrees. In some embodiments, of cannula assembly 210 having a5 mm size, the distal edge 278 of the distal tip 244 can be angled atapproximately 17 degrees relative to the plane perpendicular to thelongitudinal axis L. In embodiments of cannula assembly 210 having othersizes, for example 11 mm and 12 mm cannulae, the angle can be slightlydifferent to match the correlated cannulae 216. For example, in someembodiments of 11 mm cannula assembly, the angle θ can be approximately20 degrees, and in some embodiments of 12 mm cannula assembly, the angleθ can be approximately 12 degrees. In other embodiments of cannulaassembly 210 other angles can be used.

Advantageously, the angled distal tip 244 can greatly reduce the forcerequired to insert the cannula assembly 210 through a body wall such asthe patient's abdominal wall as compared with a distal tip having astraight tip with a distal edge perpendicular to the longitudinal axisof the cannula. Balloon trocars having straight tips have primarily beenintroduced through body walls into surgical sites through relativelylarge incisions using a cut-down technique. Desirably, the angled distaltip 244 can facilitate the use of a fixation cannula in surgicalprocedures including various cannula insertion techniques with variousincision lengths. For example, a fixation trocar having an angled distaltip can be inserted with a relatively low insertion force with insertiontechniques including insertion techniques with bladed, non-bladedoptical, or insufflation obturators.

In some embodiments, the cannula body 240 can be formed of apolycarbonate material. Desirably, the hardness and relative rigidity ofthe material allows the cannula 216 to serve as a supporting tube toinstall the flexible sleeve 218 and balloon 220 and a port to insertobturators or other medical instruments. In other embodiments, thecannula body 240 can comprise other materials, such as, for examplepolyester materials.

Sleeve

In certain embodiments, a sleeve extends from adjacent the proximal endof the trocar cannula to adjacent the distal end of the trocar cannula.The sleeve has a proximal end and a distal end with an inflatablesegment adjacent the distal end. The sleeve can be coupled to the trocarcannula at the proximal end of the sleeve and the distal end of thesleeve.

The sleeve can be coupled to the trocar cannula by a technique thatcreates a relatively low diametric profile at the coupling, hasdesirable sealing performance, and can be efficiently manufactured. Forexample, in some embodiments, the trocar cannula can have asubstantially smooth continuous outer surface, and the sleeve can becoupled to the smooth surface by application of an adhesive to form achemical bond. In other embodiments, the sleeve can be coupled to thetrocar cannula by heat welding or UV welding to create a fused coupledregion. In some embodiments, as further discussed with respect to FIGS.17-19, the sleeve can be coupled to the trocar cannula at anon-continuous region of the outer surface, such as, for example one ormore annular grooves formed therein. In some embodiments, differentcoupling techniques can be used at the proximal end of the sleeve thanare used at the distal end, while in other embodiments, substantiallysimilar coupling techniques can be used at the proximal end and thedistal end of the sleeve.

With reference to FIG. 18, an embodiment of sleeve 218 and cannulaassembly 210 is illustrated. In the illustrated embodiment, the sleeve218 comprises a proximal interface section 280 or coupler at theproximal end 281, an elongate tubular body 282 extending distally fromthe coupler, a balloon 220 positioned distal the elongate tubular body282, and a bonding segment 284 distal the balloon.

In some embodiments, the sleeve 218 can be monolithically unitarilyformed, such as by stretch blow molding. Advantageously, thestretch-blow molding process allows for a high degree of control of theballoon material, thickness and shape.

The sleeve 218 can comprise a polyolefin material such as one commonlyused as heat shrink tubing. In certain embodiments, a Sumitomo A2 clearpolyolefin tubing can be used. Advantageously, a sleeve 218 comprising apolyolefin material, is latex free, non-porous, and non-fragmenting,unlike latex or silicone rubber materials. Desirably, the polyolefintubing material can be soft, flexible, and can include a high degree ofcross-linking such that it has a relatively high strength for a givenmaterial thickness compared to other tested materials. In embodiments ofcannula assembly 210 having a polyolefin sleeve 218, despite having anincredibly thin balloon section, the balloon 220 can typically beover-inflated with an average of 5 times of a designed inflationpressure without rupturing. Also, the softness and flexibility of thepolyolefin material improves the feel of the device for the user whilealso reducing the insertion force. In other embodiments the sleeve cancomprise other materials such as a silicone material, cilran,polyisoprene, a polyurethane material, a polyurethane blend, TYGON®,VITON®, SANTOPRENE®, MYLAR®, or another suitable polymeric material.

In the illustrated embodiment, the cannula assembly includes one balloon220 positioned at a distal location on the cannula 216. It iscontemplated that in various other embodiments, additional balloons canbe incorporated to account for variations in a patient's abdominal wallthickness and anatomy. Also, balloons at different locations may usedifferent material. The balloon may be distensible or non-distensible ora combination of both. The balloon 220 in one embodiment is doughnutshaped or in one aspect disc-like. The size and/or location of theballoon 220 can vary to vary the desired retention of the trocar cannula216 with the patient's body.

With continued reference to FIG. 18, the coupler 280 is sized andconfigured to engage the cannula 216. For example, in the illustratedembodiment, the coupler 280 has a curved profile in an eccentric orgenerally teardrop shape to match the teardrop shape of the fluid dome252 of the cannula 216. Advantageously, this matching profile can allowa tight fit when the sleeve 218 is installed on to the cannula 216,reducing the potential for leakage therebetween.

In some embodiments, an outer surface of the coupler at the proximal end281 is textured. The rough surface facilitates the bonding of adhesivesto the sleeve 218, preventing the sleeve 218 from being separated fromthe cannula 216 when the balloon 220 is fully inflated. For example, aroughened or textured surface can create a plurality of relatively smallchannels which enhance flow of a chemical adhesive though a wicking orcapillary action process to create a strong adhesive bond between thesleeve 218 and the cannula 216. Desirably, a textured or roughenedsurface at the coupler can allow the sleeve 218 to comprise a materialthat can be otherwise difficult to bond with adhesives.

With continued reference to FIG. 18, the elongate tubular body 282 orshaft of the sleeve 218 extends distally from the coupler 280. The shaftis uniform and thin-walled, but thick enough to withstand slidingmovement of a retention disc 222 or other bolster.

FIG. 19 illustrates a distal end of the cannula assembly 210 with thesleeve 218 positioned on the cannula 216. Advantageously, a sleeve 218formed by a stretch blow molding process can allow for increased controlof the thickness t1 of the elongate tubular body 282 to minimize anouter diameter of the trocar cannula assembly 210 resulting in a smallerincision size for the patient. In some embodiments, the elongate tubularbody 282 can have a thickness t1 of approximately 0.008 inches toapproximately 0.012 inches.

With continued reference to FIG. 19, as illustrated, the sleeve 218comprises a non-distensible inflatable balloon 220 distal of theelongate tubular body 282. The balloon 220 can have a thickness t2 thatis smaller than the thickness t1 of the elongate tubular body 282.Advantageously, stretch blow molding a polyolefin material to form theballoon 220 can provide a high strength material with a relatively lowthickness. In some embodiments, the balloon can have a thickness betweenabout 0.0005 inches and 0.002 inches. In certain embodiments, theballoon can have a thickness of approximately 0.0015 inch.

Advantageously, abrupt thickness transitions at the balloon/shaftinterfaces can be significantly reduced or eliminated through thestretch blow molding process. Desirably, the relatively high degree ofcontrol in the balloon thickness of the stretch blow molding process canalso contribute to a minimized outer diameter adjacent the distal end ofthe cannula assembly, resulting in a reduction in insertion force.

With reference to FIG. 17, the sleeve 218 can have a chamfered leadingedge 298 at the distal end thereof. Desirably, the angle of thechamfered leading edge 298 with respect to a longitudinal axis of thebonding segment 284 can be chosen to provide a smooth transition betweenthe distal end of the cannula and the distal end of the sleeve. Such asmooth transition can contribute to a reduction in insertion force forthe trocar cannula assembly as compared with a trocar cannula assemblyhaving a generally squared corner at the distal end. In someembodiments, the angle of the chamfered leading edge 298 can be betweenapproximately 50 degrees and approximately 65 degrees relative to thelongitudinal axis of the bonding segment 284.

FIGS. 17 and 19 illustrate a cut-away detail view of the distal end ofthe cannula assembly 210 with the sleeve 218 positioned on the cannula216. In some embodiments, the outer surface 288 of the bonding segment284 at the distal end 283 of the sleeve 218 is textured, providing arough bonding surface to assist in the bonding of adhesives to thesleeve 218 by retaining adhesive and to promote flow of the adhesivesbetween the sleeve and the cannula by wicking of adhesive through acapillary action process. In some embodiments, the annular interfacesurface 274 of the annular groove 242 is textured such as with smallpits, grooves, or a roughened surface to assist in the bonding of thesleeve to the cannula. In some embodiments, a combination ofcyanoacrylate instant adhesive and UV cure adhesive can be used for thesleeve-cannula bond coupling the bonding segment 284 to the annulargroove 242. In other embodiments, other adhesives, such as only acyanoacrylate adhesive or only a UV cure adhesive, or another type ofadhesive can be used. Desirably, the adhesive can be appliedsubstantially within the annular groove 242 such that the distal end 232of the cannula 216 can have a smooth low profile transition between thesleeve 218 and the cannula 216. Advantageously, the low profiletransition between the sleeve 218 and the cannula 216 can reduce theinsertion force required to position the cannula assembly 210 in asurgical site.

In some embodiments, the low profile transition can be further enhancedby disposition of an adhesive 290 predominantly within the annulargroove 242 of the cannula body 240. The bonding segment 284 of thesleeve 218 and the annular groove 242 of the cannula 216 can be sizedand configured to facilitate the disposition of the adhesive 290predominantly within the annular groove 242. For example, in someembodiments, the annular surface of the annular groove has a firstlength l1 along the longitudinal axis of the cannula, the bondingsegment has a second length l2 along the longitudinal axis of thecannula, and the second length is smaller than the first length. Thus,in some embodiments, the annular interface surface 274 of the annulargroove 242 can comprise an engagement segment 291 and an exposed segment293. The engagement segment 291 can be defined by the second length l2and engaged by the bonding segment 284. The exposed segment 293 can bedefined by a difference between the first length l1 and the secondlength l2. The exposed segment 293 can desirably be sized to provide asufficient surface for disposition of a bead of adhesive to maintain thebonding segment 284 of the sleeve 218 with respect to the annular groove242. Thus, in some embodiments, an adhesive 290 can be at leastpartially applied to the exposed segment 293 of the annular interfacesurface 274 to couple the bonding segment 284 to the annular groove 242.

In some embodiments the sleeve 218 can be adhesively bonded to thecannula 216 at the proximal interface surface 280 or coupler with acombination of cyanoacrylate instant adhesive and UV cure adhesivesimilar to the adhesive bonding of the bonding segment 284 to theannular groove 242. In other embodiments, other adhesives, such as onlya cyanoacrylate adhesive or only a UV cure adhesive, or another type ofadhesive can be used.

Retention Disc

FIGS. 21 and 22 illustrate a retention disc 222 for positioning on thecannula assembly 210. In some embodiments, the cannula assembly 210includes a proximal fixation member such as a retention disc 222positioned proximal the balloon 220 around the elongate tubular body 282of the sleeve 218. After the trocar cannula assembly 210 is insertedthrough a body wall at a surgical site, the balloon 220 can be inflatedto maintain the position of the trocar cannula assembly 210 in thesurgical site, and the proximal fixation member or retention disc 222can prevent the trocar cannula 216 from advancing further into thesurgical site.

As illustrated in FIG. 22, the retention disc 222 can comprise agenerally circular disc with a center hole 292 defining a passage 294through the retention disc 222. The passage 294 of the center hole 292can have a ribbed profile on an inner diameter. The ribbed profile caninclude a plurality of annular grooves 296. The ribbed profile canfrictionally engage an outer surface of the elongate tubular body 282 ofthe sleeve 218 such that the retention disc 222 is manually slidablealong the sleeve 218 but tends to remain in a selected position.

In some embodiments, the retention disc 222 can be formed of anelastomeric polymer material such as a KRATON® material. A retentiondisc 222 formed of a KRATON® material can provide a desired level offrictional engagement with the outer surface of the sleeve 218 andpresent an ergonomically pleasing soft, flexible feel to a user of thetrocar cannula. Advantageously, the round corners and soft material ofthe retention disc 222 provide an atraumatic means to hold the trocar inplace. In some embodiments, the retention disc 222 can be formed by aninjection molding process. Advantageously, embodiments of a trocarcannula having a single molded retention disc 222 can have manufacturingand assembly efficiencies and facilitate ease of use relative to a clampmechanism having multiple assembled components.

In some embodiments, the trocar cannula assembly 210 can be configuredto resist movement of the retention disc 222 proximally along thecannula body 240 to prevent the trocar cannula 216 from advancingfurther into the surgical site. For example, an exterior surface 260 ofthe cannula body 240 can have a slight taper such that it has a smallerouter diameter at the distal end relative to the outer diameter at theproximal end of the cannula body. Thus, a friction force generated bythe frictional engagement between the retention disc 222 and the sleeve218 can increase as the retention disc 222 is slid proximally along thetrocar cannula 216. The retention disc 222 can be used to fixate thetrocar cannula 216 relative to a body wall. The tight fit, ribbedprofile, and tapered cannula 216 prevent the retention disc 222 fromadvancing along the cannula body 240 when an instrument is inserted intothe cannula 216.

In some embodiments, a retention disc 222 comprising an elastomericpolymer material can exhibit creep when stored under tension.Advantageously, where the exterior surface 260 of the cannula body 240includes a slight taper, before use the retention disc 222 can bepositioned adjacent the distal end having a relatively small outerdiameter when not in use to reduce the incidence of creep in theretention disc 222. During use, the retention disk 222 is advancedproximally up the shaft of the cannula 216 to an area of larger cannuladiameter, allowing placement and fixation of the disc 222. Additionally,such a tapered cannula body 240 can have further advantages inmanufacturability of the cannula body 240. For example, such a taperedprofile can facilitate release of the cannula body 240 from a mold inembodiments where the cannula body 240 is formed with an injectionmolding process.

In other embodiments, the cannula assembly 210 can comprise a bolster222′ such as a generally cylindrical or conical stability member with aclamp mechanism. For example, in some embodiments the cannula assembly210 can include a stability assembly including one of the various clampmechanisms described in U.S. Pat. No. 8,162,893, to Okihisa et al.,entitled “TROCAR STABILITY ASSEMBLY,” which is incorporated herein byreference in its entirety.

Conditioning Aid and Balloon Folding

With reference to FIG. 20, in some embodiments, a trocar assembly 210can include a conditioning aid 224 to constrict the balloon 220 relativeto the body 240 and to protect the balloon 220 during shipping.Moreover, the required insertion force can be observed to varyproportionally with an overall outer diameter of the trocar cannulaassembly 210 at the balloon 220. Thus, before use, it can be desirableto reduce insertion force by folding the balloon 220 into an insertionconfiguration having a low diameter and relatively smooth transitionfrom the distal tip 244 of the cannula 216 to the balloon 222.

A non-elastic or non-distensible balloon 220 in a deflated or insertionconfiguration does not automatically conform to the exterior surface 260of the cannula body 240. In some embodiments, the material can have atendency to wrinkle, form folds and/or creases and may project atvarious points away from the exterior surface 260 of the cannula body240. The irregularities that the un-inflated balloon may possess, canpresent resistance during insertion of the un-inflated retention balloon220 through a body wall. Folding the balloon 220 into the insertioncondition can reduce the force required for insertion. In someembodiments, in the insertion configuration the balloon 220 is foldedalong the cannula body 240 towards the proximal end 230 of the cannula216. Folding the balloon 220 towards the proximal end 230 can result inone or more folds in the balloon 220 in the insertion configuration. Forexample, in some embodiments, the balloon 220 can be folded proximallyin a single step and in other embodiments, the balloon 220 can beinitially folded distally in a first fold and subsequently foldedproximally in a second fold. By folding the balloon 220 against thetrocar placement direction, it helps reduce the insertion force andlower the balloon diametric profile. The conditioning aid 224 canmaintain the balloon 220 in the insertion configuration until it isremoved from the trocar cannula assembly 210 for insertion to a surgicalsite. Moreover, the conditioning aid 224 can protect the balloon 220and/or distal tip 244 of the cannula assembly 210 from damage duringshipping or prior to operational use.

Advantageously, a trocar cannula system can achieve have a reduceddiameter and relatively low insertion force if the conditioning aid 224is advanced over the balloon 220 to constrict the balloon 220 relativeto the body 240 when the balloon is in a formable state. For example, asfurther discussed below with respect to FIGS. 29-30, with a stretch blowmolded balloon, the conditioning aid 224 can be advanced over theballoon 220 when the balloon retains residual heat. The duration of theformable state can vary based on the material used and the thickness ofthe balloon 220. Accordingly, it can be desirable to monitor thetemperature of the balloon material and/or the elapsed time from theformation of the balloon to ensure application of the conditioning aid224 while the balloon 220 is in the formable state. The conditioning aid224 can thus constrict the formed balloon 220 against the cannula as itcools. Advantageously, constricting the balloon 220 against the cannulabody while the balloon 220 is in a formable state can achieve a lowerouter diameter relative to folding an equivalent previously-formedballoon against the cannula body. Moreover, further significantreductions in insertion force can be observed if the balloon 220 isfolded in a two-step process (with an initial distal tuck or foldfollowed by a second distal fold) while the balloon retains residualheat and before positioning of the conditioning aid 224 on the cannulabody.

FIG. 20 illustrates a conditioning aid 224 comprising a hollow tubularsegment. In the illustrated embodiment, the conditioning aid 224comprises a section of tubing having an interior surface 300 with aninner diameter. The inner diameter of the interior surface 300 is sizedto provide a snug fit over the folded balloon 220 of the trocar cannulaassembly. The illustrated tubular segment conditioning aid 224 is arelatively simple construction which can desirably provide certainmanufacturing and assembly efficiencies. In other embodiments,conditioning aids can take on many forms such as, for example, shrinktubing, a cap, a cone or a coil of appropriate inside diameter. Incertain embodiments. the conditioning aid can be made from a variety ofmaterials, including, for example, thermoplastics, thermosets, metalsand glass. In some embodiments. the conditioning aid can be generallyconical or can include a tapered interior surface to facilitate removalprior to use. Desirably, the conditioning aid can have a smooth interiorsurface to optimize conditioning and prevent damage to the balloon.

In one embodiment, It can be desired that the conditioning aid 224 isconfigured to prevent proximal movement of the conditioning aid 224 pastthe balloon 220. In some embodiments, the conditioning aid 224 is shapedto have a somewhat smaller diameter at a distal end than at a proximalend to prevent the conditioning aid 224 from moving proximally and pastthe balloon 220 to maintain the conditioning aid 224 on the balloon 220.In other embodiments, the conditioning aid 224 may have detents orprojections that prevent the conditioning aid 224 from movingproximally. In some embodiments, the cannula assembly 210 can furthercomprise a spacer between the retention disk 222 or bolster 222′ and theconditioning aid 224 to prevent the conditioning aid 224 from movingproximally past the balloon 220. The retention disk 222 or bolster 222′in one embodiment is positioned near the balloon 220 or the conditioningaid 224 is sufficiently long to contact the retention disk 222 orbolster 222′ to prevent the conditioning aid 224 from moving proximallypast the balloon 220. Preventing the conditioning aid 224 from movingproximally past the balloon 220 prevents the conditioning aid 224 fromlosing contact with the balloon 220 losing pressure and protection ofthe balloon 220 and tip 244.

Method of Manufacture

FIGS. 23-30 illustrate various embodiments of methods for manufacture oftrocars described herein. Embodiments of cannula assembly 210 discussedherein can include a preformed sleeve 218. In some embodiments, thecannula 216 can be formed from a suitable material, such as apolycarbonate or polyester material, with an injection molding process.

With reference to FIG. 29, a method of making a cannula assembly 210 isillustrated. In some embodiments, a roll of polyolefin heat-shrinktubing is cut into sections or blanks then heated to shrink the tubingdown to an installation size slightly larger than the cannula 216. Thesleeve 218 can then be positioned 402 over the cannula 216. Once theslightly oversized sleeve 218 is installed on the cannula 216, thesleeve 218 can be heated 416 to shrink onto the exterior surface 260 ofthe cannula body 240. For example, the elongate tubular body 282 of thesleeve can be formed line-to-line for installation and then heatedslightly to shrink down onto the exterior surface 260 of the cannulabody 240. The sleeve 218 is positioned 402 over the cannula 216. Thesleeve 218 can be advanced until the proximal interface section 280 ofthe sleeve 218 is positioned about a fluid inlet port 226 of the cannula216 and the bonding segment 284 of the sleeve 218 is positioned 412 inthe annular groove 242.

With reference to FIG. 29, in some embodiments, once the sleeve has beenpositioned 402 on the cannula 216, the sleeve 218 can be trimmed on theproximal end 281 and cut at the distal end 283 to form or create achamfered leading edge 298.

With reference to FIG. 29, once the preformed sleeve 218 has beenadvanced over the cannula 216 and the bonding segment 284 of the sleeve218 is positioned within the annular groove 242 of the cannula 216, thesleeve 218 can be coupled or bonded 410 to the cannula 216. For example,in some embodiments, the proximal end 281 of the sleeve 218 and thedistal end 283 of the sleeve 218 are each bonded 410 to the cannula 216.In some embodiments, the proximal interface section 280 of the sleeve218 is adhered to a location adjacent the proximal end 230 of thecannula 216 and the bonding segment 284 is adhered to the annular groove242. For example, one or more of a cyanoacrylate adhesive and a UV curebonding adhesive can be used to couple the sleeve 218 to the cannula216.

The retention disc 222 can be positioned proximally of the balloon 220around an outer surface of the sleeve 218. When installing the retentiondisc 222 on to the sleeve sub assembly 214, a fixture can be used toslightly expand the disc 222 to install over the balloon 220 and toavoid any possible balloon 220 damage.

With continued reference to FIG. 29, once the sleeve 218 has beenpositioned 402 on and bonded 410 to the cannula, the subassembly is thenlocally heated 412 at the distal end proximal to the bonding site. Theamount of material that is heated goes directly into forming the balloonand determines the wall thickness of the balloon. Excellent control ofwall thickness can be achieved by selecting the appropriate width of theheating elements that deliver heat to the section of tubing to be formedinto the balloon. For example, heating elements that are 0.200″ wideconsistently produce balloons with a perimeter wall thickness of 0.0015″(+/−0.0005″). In other embodiments, different sized heating elements canlocally heat the distal end of the sleeve 218 to form balloons havingdifferent thicknesses.

Once the sleeve is locally heated 412, an inflation fluid is applied 418to the sleeve 218 to form a balloon adjacent the distal end of thesleeve 218 proximal the bonding. FIG. 23 schematically illustratesformation of the balloon 220. In some embodiments, the balloon can beformed in a generally circular disc shape. In other embodiments, theballoon can be formed in a generally toroidal or donut shaped balloon.In other embodiments, the balloon 220 can be formed having othergeometries, such as a generally frusto-conical profile or anotherrounded profile. Advantageously, this control in balloon shape canmaximize the total working distance of the device. Furthermore, theround balloon shape and soft material provides an atraumatic means tohold the trocar assembly 210 in place.

Once the balloon is formed, the balloon can be conditioned 424 toconstrict against the cannula. For example, as illustrated in FIG. 24,the balloon 220 can be folded along the elongate tubular body 282 of thesleeve 218 towards the proximal end 230 of the cannula 216 into aninsertion configuration. As described above, significant reductions ininsertion force can be achieved by folding the balloon in a two stepprocess (an initial distal tuck or fold followed by a second proximaltuck or fold while the balloon retains residual heat). Desirably, theballoon can be conditioned 424 when the balloon retains heat from thelocal heating to enhance the constriction of the balloon. As illustratedin FIG. 30, in some embodiments, the conditioning aid 224 can then beadvanced 426 over the balloon 220 to keep the balloon 220 folded untiluse and to retain a smooth transition from cannula distal tip 244 toballoon 220. FIGS. 25 and 26 schematically illustrate such conditioningwith a conditioning aid. The interior surface of the conditioning aid224 desirably has an inner diameter D3 sized to constrict the balloon220 against the cannula body 240.

In some embodiments, at final sleeve sub assembly 214 configuration(FIG. 13), the retention disc 222 is placed relatively close to thedistal end 232 of the cannula 216 with the conditioning aid 224 flushedagainst it. The retention disc 222 acts as an anchor and prevents theconditioning aid 224 from sliding proximally past the balloon 220 priorto use. Similarly, with a position adjacent the distal end 232 of thecannula 216, the retention disc 222 can be placed at a relatively smalldiameter of the cannula body 240 to avoid stretching the inner diameterprior to use.

Various balloon 220 folding techniques can be used to provide arelatively low diametric profile to reduce insertion force for thetrocar cannula assembly. For example, in some embodiments, the balloon220 can be folded proximally upon itself in a single folding step. Usinga conditioning aid 224, the balloon 220 can be pushed against or towardsa retention disk 222 or bolster 222′ causing the balloon 220 to foldupon itself in a proximal direction. In other embodiments, as describedfurther below, the balloon 220 can be folded in a two-step process withan initial distal fold followed by a proximal fold. The balloon foldingtechnique to be incorporated in a method of manufacture for a trocarcannula assembly can be selected to provide a desired insertion forceand ease of manufacturability. Desirably, further reductions ininsertion force can be achieved if the two-step folding process isperformed when the balloon is in a formable state.

In some embodiments, subsequent to or during the extraction of air, theretention disk 222 or bolster 222′ of the trocar without a sleeve orcone (e.g., the bolster base) can be slid or pushed against a proximalend of the balloon 220 to push or apply a force distally away from theproximal end 230 of the trocar cannula 216. The distal end 306 of thebolster can be positioned adjacent the proximal end 308 of the balloon220, as illustrated schematically in FIG. 25. Using a conditioning aid224, the balloon 220 is pushed against or towards the retention disk 222or bolster 222′ causing the balloon 220 to fold upon itself in aproximal direction. A compressive force of the conditioning aid 224against the balloon 220 continues as the conditioning aid 224 slidesover the balloon 220. This sliding movement fully compresses the balloon220 into a preferred, compressed condition, as illustrated schematicallyin FIGS. 25 and 26. The conditioning aid 224 can be advanced using alinear motion or a slight twisting motion to provide a relatively lowballoon insertion profile. The retention disk 222 or bolster can bemoved proximally when the conditioning aid 224 is in place covering theentire folded balloon 222. Placement of the conditioning aid 224 overthe balloon 220 and in particular over the fold in the balloon 220maintains the fold in the balloon 220 and/or the evacuation of air fromthe balloon 220. In one embodiment, a removable base support isremovably attached to the cannula 216 and used as a support to push theproximal end of the balloon 220.

As illustrated schematically in FIG. 27-28, subjecting or applyingsterilization 310 to the balloon 220, e.g., applying gamma sterilizationto the balloon 220 further maintains the balloon 220 folded against thecannula 216 and further reduces the outer profile of the balloon 220 tobe flushed or flattened against or towards the outer surface of thecannula 216. The resulting inflation configuration of the balloon 220 isillustrated schematically in FIG. 28.

The sterilization 310 process in certain embodiments may includeelectron-beam, gamma radiation or heat. The irradiation provides a“setting” of the folded material to a predetermined condition, size andshape. The material of the compressed balloon 220 may be partiallycross-linked during this process. In the instance where heat may beapplied, a heat-shrinkable material may be used for the sleeve 218thereby compressing the balloon 220 without the friction associated withsliding a snug fitting conditioning aid 224 over the un-inflatedballoon. The irradiation process 220, in one embodiment, may involve asterilization process in which the assembled trocar cannula 216 andsleeve 218 with balloon 220 are sterilized for surgical use.

Vacuum, syringes or other air evacuation devices can be used to removethe fluid from the balloon. In one embodiment, a cap can cover thecheck-valve 228 of the trocar cannula assembly 210 to facilitatemaintenance of the evacuation of fluid from the balloon 220 and toprevent seeping of ambient air into the balloon 220. Compression orrestriction of the balloon 220 by the conditioning aid 224 facilitatesmaintenance of the evacuation of air and to prevent seeping of ambientair into the balloon 220. As a balloon trocar cannula assembly 210 maybe turned and torqued against the body cavity or incision during use, aballoon 220 may rupture. The folding of the balloon 220 does notincrease the likelihood of balloon 220 rupture and prevents potentialdamage to the balloon 220 during insertion. In one embodiment, furtherapplication of the syringe or other air evacuation devices to remove airfrom the balloon are applied while the conditioning aid 224 is placed orremains on the balloon 220, during and/or after sterilization and/orprior to removal of the conditioning aid 224.

With reference to FIG. 31, as illustrated, some embodiments of balloontrocar including a conditioning aid 224 applied while the balloon was ina formable state (plotted as a dotted line) can have a reduced insertionforce profile as compared with an equivalent balloon trocar having aballoon formed without a conditioning aid (plotted as a solid line).FIG. 31 illustrates insertion force versus insertion depth (as comparedwith reference positions along the cannulae, illustrated schematicallyabove the plotted insertion force profiles) of various exemplary balloontrocar cannulae. The lightened line illustrates a reduction in insertionforce local maxima or ‘peaks’ for an exemplary trocar cannula assemblyhaving a balloon with a chamfered leading edge 298 and formed with aconditioning aid 224 as further discussed herein as compared with anexemplary balloon trocar cannula without these aspects. For example, atreference position 5 a local insertion force maximum can be reduced by aballoon formed with a conditioning aid. It is contemplated that certainadvantageous reductions in insertion force maxima can be achieved by aballoon trocar cannula having one or both of these aspects.

Although this application discloses certain preferred embodiments andexamples, it will be understood by those skilled in the art that thepresent inventions extend beyond the specifically disclosed embodimentsto other alternative embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Further, the variousfeatures of these inventions can be used alone, or in combination withother features of these inventions other than as expressly describedabove. Thus, it is intended that the scope of the present inventionsherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of claims which follow.

What is claimed is:
 1. A cannula assembly comprising: a cannula having aproximal end, a distal end opposite the proximal end, and a lumenextending from the proximal end to the distal end along a longitudinalaxis, the lumen configured to receive a surgical instrument therein, thecannula comprising: a generally tubular cannula body having an exteriorsurface and a first outer diameter; and an annular recess formed in theexterior surface of the cannula body adjacent the distal end of thecannula, the annular recess transverse to the longitudinal axis, theannular recess having a second outer diameter smaller than the firstouter diameter of the cannula body; and a sleeve having a proximal endand a distal end, the sleeve disposed around the cannula from adjacentthe proximal end of the cannula to the annular recess, the sleevecomprising: an elongate tubular body; a balloon positioned distal theelongate tubular body; and a chamfered leading edge at the distal end ofthe sleeve; and wherein the distal end of the sleeve is coupled to theannular recess of the cannula body at a low profile transition.
 2. Thecannula assembly of claim 1, wherein the sleeve further comprises abonding segment distal the balloon.
 3. The cannula assembly of claim 2,wherein the bonding segment defines a longitudinal axis, and wherein thechamfered leading edge defines an angle of between approximately 50degrees and approximately 65 degrees relative to the longitudinal axisof the bonding segment.
 4. The cannula assembly of claim 1, wherein theannular recess has a textured surface.
 5. The cannula assembly of claim1, wherein the sleeve is monolithically unitarily formed.
 6. The cannulaassembly of claim 1, further comprising a conditioning aid removablydisposed around the balloon.
 7. The cannula assembly of claim 1, furthercomprising an adhesive substantially within the annular recess to couplethe distal end of the sleeve to the annular recess.
 8. The cannulaassembly of claim 7, wherein the distal end of the sleeve is positionedin the annular recess to define an exposed segment of the annularrecess, the exposed segment sized to receive the adhesive.
 9. Thecannula assembly of claim 1, wherein the elongate tubular body has afirst thickness, and the balloon has a second thickness smaller than thefirst thickness.